Mobile Multimedia Broadcast Transmission System

1. A mobile multimedia broadcast transmission system, comprising: a Reed-Solomon (RS) coding and byte interleaving unit for RS coding and byte interleaving an upper layer data stream through a physical logical channel; a Low Density Parity Check (LDPC) coder for LDPC coding the data output from the RS coding and byte interleaving unit to obtain bit data; a bit interleaver for bit interleaving the bit data output from the LDPC coder; a constellation mapper for constellation mapping the data output from the bit interleaver; a frequency domain symbol generator for multiplexing discrete pilots, continuous pilots containing system information and constellation mapped data symbols into OFDM frequency domain symbols; a scrambler adapted for scrambling the OFDM frequency domain symbols with a pseudo-random sequence; an Inverse Fast Fourier Transformer (IFFT) for IFFT transforming the frequency domain symbols output from the scrambler to generate OFDM time domain symbols; a time domain framer for forming the OFDM time domain symbols into time slots and concatenating the time slots into a physical layer signal frame; and a transmitter for converting the physical layer signal frame from baseband to radio frequency for transmission, wherein the transmitter is configured for signal transmission over any 6 MHz bandwidth in a wireless channel, and wherein the physical layer signal frame has a duration of one second and includes 40 time slots each having a duration of 25 ms, each time slot including one beacon and 53 OFDM symbols, the beacon including one transmitter identification signal and two identical sync signals, the transmitter identification signal is identified by 141-bit information, carried by a number N ID =256 of sub-carriers and modulated with BPSK, the transmitter identification signal TxID(k) being generated by mapping a transmitter identification sequence according to: X ID ⁡ ( i ) = { 1 - 2 × TxID ⁡ ( i - 1 ) , 1 ≤ i ≤ 70 0 , i = 0 ⁢ ⁢ or ⁢ ⁢ 71 ≤ i ≤ 184 1 - 2 × TxID ⁡ ( i - 115 ) , 185 ≤ i ≤ 255.

2. The mobile multimedia broadcast transmission system according to claim 1 , wherein, the transmitter identification signal being obtained by BPSK mapping, IFFT transforming and periodically spreading a frequency domain random sequence, each of the sync signals being obtained by BPSK mapping and IFFT transforming a truncated frequency domain random sequence.

3. The mobile multimedia broadcast transmission system according to claim 2 , wherein the sync signal S b (t) is a band-limited pseudo-random signal having a duration T b of 204.8 μs: S b ⁡ ( t ) = 1 N b ⁢ ∑ i = 0 N b - 1 ⁢ X b ⁡ ( i ) ⁢ ⅇ j ⁢ ⁢ 2 ⁢ ⁢ π ⁢ ⁢ ⅈ ⁡ ( Δ ⁢ ⁢ f ) b ⁢ t , 0 ≤ t ≤ T b , where N b is the number of sub-carriers for carrying the sync signal, X b (i) is a BPSK modulated signal carrying a binary pseudo-random sequence X b (i), and (Δf) b is the sub-carrier interval for the sync signal; wherein N b =2048, and the BPSK modulated signal X b (i) for PN b (k) is generated by mapping PN b (k) according to: X b ⁡ ( i ) = { 1 - 2 × PN b ⁡ ( i - 1 ) , 1 ≤ i ≤ 568 0 , i = 0 ⁢ ⁢ or ⁢ ⁢ 569 ≤ i ≤ 1479 1 - 2 × PN b ⁡ ( i - 912 ) , 1480 ≤ i ≤ 2047.

4. The mobile multimedia broadcast transmission system according to claim 3 , wherein the binary pseudo-random sequence is generated by a linear feedback shift register having an initial value of 01110101101 and a generation polynomial of x 11 +x 9 +1.

5. The mobile multimedia broadcast transmission system according to claim 2 , wherein the transmitter identification, the sync sequence and the OFDM symbols overlap with each other with a guard interval having a window function, the window function having an expression of: w ⁡ ( t ) = { 0.5 + 0.5 ⁢ ⁢ cos ⁡ ( π + π ⁢ ⁢ t / T GD ) , 0 ≤ t ≤ T GD 1 , T GD < t < T + T GD 0.5 + 0.5 ⁢ ⁢ cos ⁡ ( π + π ⁡ ( T - t ) / T GD ) , T + T GD ≤ t ≤ T + 2 ⁢ ⁢ T GD , where t is a temporal variable, T is a constant and T GD is the duration of the guard interval.

6. The mobile multimedia broadcast transmission system according to claim 1 , wherein the RS coding is based on a truncated code of RS(192, K) obtained by truncating an original system code of RS(255, M), where M=K+63, K is the number of bytes of information sequence in one codeword, each code element of the system code of RS(255, M) being taken from GF(256) field having a generation polynomial of p(x)=x 8 +x 4 +x 3 +x 2 +1.

7. The mobile multimedia broadcast transmission system according to claim 6 , wherein the RS(192, K) code comprises four modes having the K value of 192, 168, 160 and 144, respectively.

8. The mobile multimedia broadcast transmission system according to claim 7 , wherein the expression of the generation polynomial for the RS(192, K) code is g ⁡ ( x ) = ∑ i = 0 192 - K ⁢ g i ⁢ x i , and wherein for K=192, the coefficient g i in the expression of the generation polynomial for RS(192, 192) is i g i 0 1 for K=168, the coefficient g i in the expression of the generation polynomial for RS(192, 168) is i g i 0 193 1 108 2 199 3 208 4 173 5 79 6 45 7 133 8 251 9 125 10 44 11 167 12 198 13 150 14 174 15 252 16 218 17 8 18 197 19 195 20 20 21 33 22 197 23 244 24 1 for k=160, the coefficient in the expression of the generation polynomial for RS(192, 160) is i g i 0 45 1 216 2 239 3 24 4 253 5 104 6 27 7 40 8 107 9 50 10 163 11 210 12 227 13 134 14 224 15 158 16 119 17 13 18 158 19 1 20 238 21 164 22 82 23 43 24 15 25 232 26 246 27 142 28 50 29 189 30 29 31 232 32 1 for k=144, the coefficient in the expression of the generation polynomial for RS(192, 144) is i g i 0 228 1 231 2 214 3 81 4 113 5 204 6 19 7 169 8 10 9 244 10 117 11 219 12 130 13 12 14 160 15 151 16 195 17 170 18 150 19 151 20 251 21 218 22 245 23 166 24 149 25 183 26 109 27 176 28 148 29 218 30 21 31 161 32 240 33 25 34 15 35 71 36 62 37 5 38 17 39 32 40 157 41 194 42 73 43 195 44 218 45 14 46 12 47 122 48 1.

9. The mobile multimedia broadcast transmission system according to claim 8 , wherein the upper layer data stream is input to the RS coding and byte interleaving unit in a column-wise manner from left to right in units of bytes, and wherein the RS coding is carried out in a row-wise manner and the start byte of the byte interleaving unit is mapped onto the start point of a particular time slot for transmission.

10. The mobile multimedia broadcast transmission system according to claim 9 , wherein the block output from the LDPC coder has a length of 9216 bits and code rates of 1/2 and 3/4, respectively, and wherein the interleaving modes of the byte interleaving unit corresponding to the code rates are: 1/2 LDPC Code 3/4 LDPC Code Interleaving Mode 1 MI = 66 MI = 99 Interleaving Mode 2 MI = 132 MI = 198 Interleaving Mode 3 MI = 264 MI = 396 where MI is the number of rows for the byte interleaving unit which having MI×192 bytes in total.

11. The mobile multimedia broadcast transmission system according to claim 1 , wherein the bit interleaver is configured as a 384×264 block interleaver, the bit data output from the LDPC coder is sequentially written into each row of the block interleaver in a top-down order until the entire block interleaver is fully filled and then sequentially read out in a column-wise manner from left to right, and wherein the output from the bit interleaver is aligned with the time slots.

12. The mobile multimedia broadcast transmission system according to claim 1 , wherein the frequency domain symbol generator is configured to multiplex, in each OFDM symbol, 284 discrete pilots, 78 continuous pilots and 1914 data sub-carriers into 2276 effective sub-carriers.

14. The mobile multimedia broadcast transmission system according to claim 13 , wherein, for an OFDM symbol numbered n in each time slot, the sub-carriers corresponding to the discrete pilots in the OFDM symbol are numbered as m, where if ⁢ ⁢ mod ⁡ ( n , 2 ) = 0 m = { 8 ⁢ ⁢ p + 1 , p = 0 , 1 , 2 , … ⁢ , 141 8 ⁢ ⁢ p + 3 , p = 142 , 143 , 144 , … ⁢ , 283 ⁢ ⁢ if ⁢ ⁢ mod ⁡ ( n , 2 ) = 1 ⁢ ⁢ m = { 8 ⁢ ⁢ p + 5 , p = 0 , 1 , 2 , … ⁢ , 141 8 ⁢ ⁢ p + 7 , p = 142 , 143 , 144 , … ⁢ , 283 , and the values of the discrete pilots are all 1+0j.

15. The mobile multimedia broadcast transmission system according to claim 1 , wherein the generation polynomial for the pseudo-random sequence used by the scrambler is, and the scramble code has eight patterns corresponding to the following initial values of the register, respectively: 1) Scramble Code Pattern 0—Initial value 0000 0000 0001, 2) Scramble Code Pattern 1—Initial value 0000 1001 0011, 3) Scramble Code Pattern 2—Initial value 0000 0100 1100, 4) Scramble Code Pattern 3—Initial value 0010 1011 0011, 5) Scramble Code Pattern 4—Initial value 0111 0100 0100, 6) Scramble Code Pattern 5—Initial value 0100 0100 1100, 7) Scramble Code Pattern 6—Initial value 0001 0110 1101, 8) Scramble Code Pattern 7—Initial value 1010 1011 0011; and wherein the pseudo-random sequence is reset at the start of each time slot such that all of the time slots are scrambled with the same pattern.

16. The mobile multimedia broadcast transmission system according to claim 1 , wherein the IFFT unit is configured to place the 2276 effective sub-carriers in sub-carriers 1 - 1138 and 2958 - 4095 of 4096 sub-carriers for a 4096-point IFFT operation.

17. The mobile multimedia broadcast transmission system according to any one of claims 1 to 16 , wherein the time domain framing unit is configured to add a guard interval, a sync signal and a transmitter identification signal sequentially to a modulated OFDM symbol to form a time slot and to concatenate 40 time slots into a physical layer signal frame.